Improve image visibility

[LuD1161]

Current Implementation :

When clicking the image in modal, it looks like this :

After this PR :

When clicking the image in modal, it looks like this :

[PierreCapo]

Hello @LuD1161 thanks again for all of your PRs, that's super cool 😍 On this one, I'll need to test a bit more, since handling images in Tweets was particularly tricky. Typically, it needs also to handle properly both single and multiple images. I'll have a closer look in some hours